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Diarrhoea and constipation link to faster accumulation of heat pain in women

Ye, DiORCID: 0000-0003-0668-2666 (2019) Diarrhoea and constipation link to faster accumulation of heat pain in women. Honours thesis, Murdoch University.

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The cause of chronic abdominal pain in irritable bowel syndrome remains unclear. This study linked gut microbiome (GM; a recently proposed cause) with pain modulation (an established cause). GM composition was inferred by stool consistency (measured on the Bristol Stool Scale). Pain modulation was tested using the conditioned pain modulation paradigm, where a “pain-inhibits-pain” phenomenon was examined. Participants were 24 women with or without irritable bowel syndrome. First, women with diarrhoea or constipation (reflecting imbalanced GM composition) and women with normal stools showed no pain inhibition to electrical stimuli after heat conditioning. Lack of pain inhibition in both groups may be due to inappropriate study design (e.g., short delay after preliminary pain sensitivity tests and mildly painful stimuli). Second, women with diarrhoea or constipation had a faster accumulation of pain when their forearm was heated than women with normal stool consistency. This finding suggests a link between imbalanced GM composition and heightened pain facilitation. However, the results must be interpreted cautiously because of confounds, such as stimulus intensity and unpleasantness level. Major implications for future studies are (a) to develop a standardised conditioned pain modulation testing protocol, (b) to measure distress or anxiety levels during the testing, (c) to measure the unpleasantness of painful stimuli together with pain intensity, (d) to use an accurate measure of GM composition, and (e) to replicate the findings in large sample.

Item Type: Thesis (Honours)
Murdoch Affiliation(s): Psychology, Counselling, Exercise Science and Chiropractic
Supervisor(s): Drummond, Peter and Vo, Lechi
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